Field
The present invention generally relates to a transparent electronic display board capable of producing a uniform optical output. More particularly, the present invention relates to a transparent electronic display board capable of producing a uniform optical output, in which a driving voltage applied to a light-emitting element can be uniformly supplied within a constant range by adjusting the width and length of patterns according to the sheet resistance of a transparent electrode, so that multiple light sources installed in the transparent electronic display board can emit light at uniform intensity, thus producing a uniform optical output.
Description of the Related Art
Generally, an electronic display board using neon, a cold cathode lamp (CCL), or a light emitting diode (LED) is widely used as an outdoor light-emitting device. Also, an external electrode fluorescent lamp (EEFL), a cold cathode fluorescent lamp (CCFL), a light-emitting diode electronic display board, or the like is used as an indoor light-emitting device.
In this case, neon or a cold cathode lamp is disadvantageous because it consumes excessive power due to the use of high-voltage power, has the risks of electric shock and fire, and has a short lifespan. Also, an EEEL or a CCFL is disadvantageous because outdoor use is difficult due to the high frequency use, and because it has low illuminance and a short lifespan.
Also, an electronic display board using an LED is characterized in that it emits light only in one direction because the back of the light emitting surface is blocked by a cover plate due to the processing of an electric wire or a black membrane.
On the other hand, contemporary light-emitting devices are being used as advertising boards rather than merely just for lighting, or are widely used for interior decoration design wherein an aesthetic sense is added.
However, the aforementioned light emitting devices have a limitation in assigning an aesthetic sense due to constraints such as the size of the lamp and the size of the stand or the like supporting such a light-emitting device.
Consequently, in the past, to assign the above-described aesthetic sense to a light-emitting device, a transparent electronic display board was released, in which multiple light-emitting elements were attached to a transparent electrode and were configured to emit light using a controller, thus displaying characters or figures on the transparent electrode, and also representing videos. In the transparent electronic display board, multiple light-emitting elements form connectivity patterns on a transparent electrode. Typically, as the light-emitting elements, light-emitting elements having a two-electrode structure, a three-electrode structure, and a four-electrode structure were used. A view of connectivity patterns of a transparent electronic display board to which four-electrode light-emitting elements are applied, among conventional transparent electronic display boards, is illustrated in FIG. 1.
Illustrated in FIG. 1 is an exemplary view of the connectivity patterns for conventional transparent electronic display boards using four-electrode light-emitting elements.
Referring to FIG. 1, the conventional transparent electronic display board includes multiple light-emitting elements 1 fixedly bonded by transparent resin between two transparent electrodes 2 disposed opposite each other; connectivity patterns 2a to 2d of the transparent electrodes, connected to any one electrode of each light-emitting element 1 via a coating on the transparent electrode 2; and conductive tape 2a′ to 2d′ configured to guide power to the connectivity patterns 2a to 2d of the transparent electrodes.
The multiple light-emitting elements 1 are four-electrode light-emitting elements 1, in which one cathode electrode and three anode electrodes are formed, and the electrodes are respectively connected to connectivity patterns 2a to 2d extending from different transparent electrode conductive tapes. Here, the multiple light-emitting elements 1 are vertically arranged in a line, and multiple lines in which the light-emitting elements 1 are vertically aligned are formed.
The connectivity patterns 2a to 2d are extended from the transparent electrode conductive tape, and are respectively connected to the anode electrodes and cathode electrode of the corresponding four-electrode light-emitting element 1. Here, the connectivity patterns 2a to 2d have separate shapes insulated from each other so that they are not in contact with each other.
Further, the connectivity patterns 2a to 2d have shapes extending from both ends to the light-emitting elements 1 sequentially aligned in a center portion. That is, to function as a ground terminal, the first connectivity pattern 2a connected to the cathode electrode and the second to fourth connectivity patterns 2b to 2d connected to the anode electrodes are sequentially connected. Behind the fourth connectivity pattern 2d, fifth to seventh connectivity patterns 2e to 2g connected to anode electrodes are extended again. Here, the first connectivity pattern 2a connected to the cathode electrode is formed again subsequently to the seventh connectivity pattern 2g connected to an anode electrode.
Therefore, the conventional transparent electronic display board is problematic because a connectivity pattern connected to the cathode electrode of the light-emitting element and used as a ground terminal, is set according to the number of light-emitting elements aligned in a vertical or horizontal direction, meaning, man-hours are added in the manufacturing process, thus increasing manufacturing costs and deteriorating productivity.
Further, since the conventional transparent electronic display board has different light-emitting element locations, extended lengths of the connectivity patterns connected to the electrodes of the respective light-emitting elements are different from each other, but the widths thereof are identical to each other.
Since the conventional transparent electronic display board has the sheet resistance of the transparent electrode itself and resistance per unit area of each connectivity pattern, the range of voltage loss differs depending on the widths and lengths of the connectivity patterns, so that a drive voltage applied to a light-emitting element connected at the location where the length of a connectivity pattern is extended as the longest length is different from a drive voltage applied to a light-emitting element connected at the location where the length of the connectivity pattern is the shortest.
Accordingly, the conventional transparent electronic display board is problematic in that, as drive voltages falling within different ranges are applied to respective light-emitting elements fixed at different locations, and are used to drive the light-emitting elements, non-uniform light is output at different intensities, thus making it difficult to implement clear image quality upon displaying images or videos.
The present invention has been made keeping in mind the above problems, and one aspect of the present invention is to provide a transparent electronic display board, in which the widths of connectivity patterns required to supply power to light-emitting elements in the transparent electronic display board are selectively formed in consideration of the sheet resistance and length of each transparent electrode, thus enabling all light-emitting elements to exhibit a uniform optical output.